How to Build Your Own Drinking Bird

Just about everyone has seen the famous Drinking Bird. Give him a tip and he will bob and drink for hours. Not many people realise that this little guy is actually an example of the Second Law of Thermodynamics, which states that within a closed system energy can neither be created nor destroyed. This fun toy is a tiny thermal engine, using the heat deferential between its head and its tail to keep moving.

Skill level:

Easy

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Things you need

Glass bulbs (2)

Glass tube that fits into the bulbs

Methylene chloride

Super glue

Air pump

Metal wire

Stand

Felt

Glue

Accessories

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Instructions

1

Fill one of the glass bulbs with a small amount of methylene chloride. This will be the tail end.

2

Insert the glass tube into the methylene chloride bulb almost all the way to the bottom. Seal it in place with super glue.

3

Insert the other end of the tube a little into the other bulb, just enough to seal it in place. This will be the head.

4

Seal the second bulb almost all the way around, leaving a little room to suck out the air.

5

Remove the air from the bird with an air pump and finish sealing the second bulb.

6

Wrap a piece of wire around the centre of the tube to act as a pivot. Glue the wire in place.

7

Create a head and beak on the head end with felt and glue. You can decorate it as much as you want with accessories like googly eyes.

8

Place the bird on a stand so it can pivot back and forth. When it is at rest it should lean slightly forward. If it does not, adjust the wire until it does.

9

Tip the beak into a glass of water and watch it go!

Tips and warnings

Here's how the bird works: When the felt is soaked with water, it cools the head through evaporation. This temperature difference draws the methylene chloride up the tube. The shift in weight causes the head to dip down into the glass of water. Tipping over allows the methylene chloride to return to the tail. The bird will right itself again, but it has soaked more water into the felt which starts the whole process over.